This invention relates to measurement devices, and more particularly to an adapter for a levelmeter, which enables the levelmeter to be remotely monitored.
Level sensing is used for a vast number of applications, perhaps the most familiar being for tanks containing liquids, such as fuel tanks. A limit levelmeter (also known as a switch levelmeter) provides readings at one or more predetermined levels. For example, a limit levelmeter may provide a reading only at a predetermined low level. A continuous levelmeter provides a continuous range of measurements from empty to full.
There are many different types of level meters, each type having a different principle of operation. Some of the more common types are float levelmeters, capacitive levelmeters, photoelectric levelmeters, and ultrasonic levelmeters.
Most levelmeters are designed to provide a readout at the meter. However, in light of today""s ever increasing data networking capabilities, there is a demand for remote monitoring. Today, this is typically accomplished by removing a mechanical reading dial and replacing it with an electronic data device.
One aspect of the invention is a remote monitoring adapter for use with a levelmeter. It is assumed that the levelmeter is a mechanical device having a rotating magnet that operates a read out mechanism, such as a needle dial. The adapter comprises a probe having thin flat plate upon which is mounted at least one hall sensor operable to respond to motion of the magnet. The probe is of a size and shape suitable for insertion between the magnet and the read out mechanism. The adapter also has a processing unit that receives an output signal from each hall sensor and converts the sensor output to digital data representing a level of liquid. A transmitter is operable to provide a signal that represents the digital data and that may be transmitted to a remote monitoring unit.
One advantage of the invention is that the adapter does not modify the performance of the original levelmeter. In other words, the levelmeter""s reading dial may still be read in the same manner as before installation of the adapter. Installation of the adapter is simple and quick. It can be installed in a tank already containing liquid; it is not necessary to empty the tank before installation.
The adapter is a low cost device. It can make either digital or analog readings, and can measure both liquid level and rate of consumption.